The Treasury Department auctioned $33 billion in three-month bills at a discount rate of 0.095 percent, up from 0.08 percent last week. Another $31 billion in six-month bills was auctioned at a discount rate of 0.145 percent, up from 0.130 percent last week.

The three-month rate was the highest since three-month bills averaged 0.115 percent two weeks ago on Feb. 27. The six-month rate was the highest since these bills averaged 0.150 percent on Aug. 1.

The discount rates reflect that the bills sell for less than face value. For a $10,000 bill, the three-month price was $9,997.60, while a six-month bill sold for $9,992.67. That would equal an annualized rate of 0.096 percent for the three-month bills and 0.147 percent for the six-month bills.

Separately, the Federal Reserve said Monday that the average yield for one-year Treasury bills, a popular index for making changes in adjustable rate mortgages, was unchanged 0.18 percent, the same as the previous week.